Actually you just need to have Java installed, which you said you have, open the Battle Simulator (just click once on the link, and once on "OK" while the topmost bullet point is active, and everything else should be self-explanatory.

Perhaps you do know someone with more experience in computer related stuff who could show you in real life? He could find out any problems and solve them right there with you.

Currently it looks like you do not know what you need to tell me so that i can help you, and i do not know what i need to know to help you. Things you could solve in five minutes face to face take often ages without, so if you know somebody in your vicinity...